"We know that he unlawfully entered her home," police spokeswoman Ashley Savage said. "How exactly he ended up inside the residence, that's still under investigation."

Nothing inside the home was taken, police said.

"You feel safest in your home, and that's why we're using all the resources we have available to investigate this incident," Savage said. "If [you] saw anything that evening that was suspicious, please come forward and report it to the Arlington County police.

The suspect, who police believe is the same man the woman saw before the attack, was wearing a dark jacket with a hood and driving a tan-colored four-door sedan.

Police searched the area using dogs. The investigation continues.

Police are investigating whether the attack may be related to another incident early Sunday. A woman told police she was walking home when a man followed her. She went inside and he banged on her door repeatedly, police said.

Anyone with information on the attack or the suspect is asked to call police at 703-228-4198. To submit information anonymously, call 1-866-411-TIPS.